After years of strident denials, Armstrong publicly confessed to using performance-enhancing drugs during his storied cycling career. The confession came several months after he was stripped of his seven Tour de France titles and banned from elite competition on the heels of a damning USADA report implicated him in the "the most sophisticated, professionalized and successful doping program that sport has ever seen."

Per ABC's unnamed source, federal "agents are actively investigating Armstrong for obstruction, witness tampering and intimidation" relating to his PED use and the aggressive tactics he used to silence those who previously attempted to come forward with the truth.

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This report comes on the heels of a contradictory statement from U.S. attorney Andre Birotte to reporters that Armstrong's confession would not alter the government's decision not to pursue charges. In February 2012, the government announced that it was closing an investigation into Armstrong and would not be pursuing charges. According to Birotte, Armstrong's subsequent confession would not alter that decision.

"We made a decision on that case a little over a year ago. Obviously, we've been well aware of the statements that have been made by Mr. Armstrong in other media reports," Birotte said in Washington on Tuesday. "That does not change my view at this time."

Even if the investigation helmed by Birotte will not be reopened and the separate investigation revealed to ABC never brings formal charges, the Food And Drug Administration is still pursuing the case, according to USA Today Sports.

"When the U.S. Attorney's Office declines to prosecute an individual or entity, typically law enforcement agencies do not pursue further investigative activities," FDA spokeswoman Sarah Clark-Lynn told USA Today Sports. "That said, this is an ongoing matter for the agency and I cannot comment further."